The present invention relates to the washing machine sector and, in particular, to the problem of disposing of the used washing liquid.
Machines for washing components, in particular metal components for industrial use, are currently known, comprising a supporting frame which defines a tank or washing chamber and a mobile lid that can be opened and closed to allow insertion of the components in the tank, support means for the components in the tank and means which spray water and detergents dissolved in said water onto the components.
In such known washing machines the water is stored in the bottom of the tank or in a separate tank and repeatedly recirculated over the components. Thus, after a given number of washing cycles, despite the presence of filters which attempt to purify the washing water, said water becomes overloaded with washing residues, such as dust, grease, metal chippings and various residues present on the components before washing. When the water contains an excessive level of residues--for example every 15-30 days--it is substituted with clean water in which fresh detergent is dissolved. The remaining waste water contains a high level of pollutants and disposing of it is problematic and expensive. Companies which carry out this type of washing must install special chemical-physical purifiers outside the facility in order to subject the waste water to costly purification processes before disposing of it in the sewer network. If they are not equipped with such purification plant, they must acquire storage tanks for the temporary storage of the waste water, which must subsequently be transported to purifiers located at a distance from the working facility. Such waste water purification operations are expensive and inconvenient.